/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    https://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 */
package org.grails.gsp.jsp

import jakarta.servlet.ServletContext
import jakarta.servlet.jsp.PageContext as PC

import org.springframework.web.context.request.RequestContextHolder

import org.grails.gsp.GroovyPageBinding
import org.grails.web.pages.GroovyPagesServlet
import org.grails.web.servlet.mvc.GrailsWebRequest
import org.grails.web.util.GrailsApplicationAttributes as GAA

/**
 * Obtains a reference to the GroovyPagesPageContext class.
 *
 * @author Graeme Rocher
 * @since 1.0
 */
class PageContextFactory {

    static GroovyPagesPageContext getCurrent() {
        GrailsWebRequest webRequest = RequestContextHolder.currentRequestAttributes()

        def request = webRequest.getCurrentRequest()

        def pageContext = request.getAttribute(PC.PAGECONTEXT)
        if (pageContext instanceof GroovyPagesPageContext) return pageContext

        ServletContext servletContext = webRequest.getServletContext()
        def gspServlet = servletContext.getAttribute(GroovyPagesServlet.SERVLET_INSTANCE)
        if (!gspServlet) {
            gspServlet = new GroovyPagesServlet()
            servletContext.setAttribute(GroovyPagesServlet.SERVLET_INSTANCE, gspServlet)
        }
        def pageScope = request.getAttribute(GAA.PAGE_SCOPE)
        if (!pageScope) {
            pageScope = new GroovyPageBinding()
            request.setAttribute(GAA.PAGE_SCOPE, pageScope)
        }

        pageContext = new GroovyPagesPageContext(gspServlet, pageScope)
        request.setAttribute(PC.PAGECONTEXT, pageContext)

        return pageContext
    }
}
